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Avdonin V.V.,Moscow State University | Mel'nikov M.E.,Yuzhmorgeologiya | Sergeeva N.E.,Moscow State University
Moscow University Geology Bulletin | Year: 2013

The results of the study of submicroscopic structures of oceanic oxide ores are described. The objects of study were Co-bearing Fe-Mn crusts from the Magellan Seamounts and Fe-Mn nodules from the Clarion-Clipperton province. The evolution of structural elements is traced in the crust section from the Lower Campanian-Maastrichtian to Pliocene-Quaternary layers. It was found that growing nodules actively entrap hosting sediments into the layered cover. The entrapment mechanism of sediments by nodules was revealed. © 2013 Allerton Press, Inc.

Novikov G.V.,RAS Shirshov Institute of Oceanology | Yashina S.V.,Rosnedra | Mel'nikov M.E.,Yuzhmorgeologiya | Vikent'ev I.V.,RAS Institute of Geology and Mineralogy | Bogdanova O.Y.,RAS Shirshov Institute of Oceanology
Lithology and Mineral Resources | Year: 2014

The results of experimental studies of ion exchange properties of Co-bearing ferromanganese crusts in the Magellan Seamounts (Pacific Ocean) are discussed. Maximum reactivity in reactions with the participation of manganese minerals (Fe-vernadite, vernadite) is typical of Na+, K+, and Ca2+ cations, whereas minimum activity is recorded for cations Pb2+ and Co2+. The exchange complex of ore minerals in crusts is composed of Na+, K+, Ca2+, Mg2+, and Mn2+ cations. The exchange capacity of manganese minerals increases from the alkali metal cations to rare and heavy metal cations. Peculiarities of the affiliation of Co2+, Mn2+, and Mg2+ cations in manganese minerals of crusts are discussed. In manganese minerals, Co occurs as Co2+ and Co3+ cations. Metal cations in manganese minerals occur in different chemical forms: sorbed (Na+, K+, Ca2+, Mn2+, Co2+, Cu2+, Zn2+, Cd2+, and Pb2+); sorbed and chemically bound (Mg2+, Ni2+, Y3+, La3+, and Mo6+); and only chemically bound (Co3+). It is shown that the age of crust, its preservation time in the air-dry state, and type of host substrate do not affect the ion exchange indicators of manganese minerals. It has been established that alkali metal cations are characterized by completely reversible equivalent sorption, whereas heavy metal cations are sorbed by a complex mechanism: equivalent ion exchange for all metal cations; superequivalent, partly reversible sorption for Ba2+, Pb2+, Co2+, and Cu2+ cations, relative to exchange cations of manganese minerals. The obtained results refine the role of ion exchange processes during the hydrogenic formation of Co-bearing ferromanganese crusts. © 2014 Pleiades Publishing, Inc.

Novikov G.V.,RAS Shirshov Institute of Oceanology | Mel'nikov M.E.,Yuzhmorgeologiya | Bogdanova O.Y.,RAS Shirshov Institute of Oceanology | Vikent'ev I.V.,RAS Institute of Geology and Mineralogy
Lithology and Mineral Resources | Year: 2014

Communication 1 of the present paper is devoted to various aspects of the hydrogenic ferromanganese crusts in the western and eastern clusters of the Magellan Seamounts in the Pacific. It was revealed that crusts are developed on guyots as a continuous sheet of Fe-Mn minerals on exposures of primary rocks. They commonly make up ring-shaped deposits along the periphery of the summit surface and in the upper sectors of slopes. Thickness of the crust varies from n to ∼18 cm and shows irregular variations in separate layers. Irrespective of the geographic position, crusts are composed of four layers-two lower phosphatized (I-1 and I-2) and two upper nonphosphatized (II and III) layers. The crusts differ in terms of structure and texture, but they are sufficiently similar within separate layers (I-1, I-2, and others). The major ore minerals in crusts are commonly represented by poorly crystallized and low-ordered minerals (Fe-vernadite and Mn-feroxyhyte); the subordinate mineral, by the well-crystallized and ordered vernadite. It has been established that heavy and rare metal cations are concentrated extremely irregularly in ore minerals of the crusts, suggesting a pulsating mode of their input during different geological epochs. © 2014 Pleiades Publishing, Inc.

Novikov G.V.,RAS Shirshov Institute of Oceanology | Mel'nikov M.E.,Yuzhmorgeologiya | Lobkovsky L.I.,RAS Shirshov Institute of Oceanology | Bogdanova O.Y.,RAS Shirshov Institute of Oceanology | Sorokhtin N.O.,RAS Shirshov Institute of Oceanology
Doklady Earth Sciences | Year: 2015

The data on the geological structure of different guyots on the Marcus-Wake rise with cobalt-bearing Fe–Mn crusts are discussed. Crusts are represented by three-layer aggregates composed of one lower phosphatized (I-1) and two upper non-phosphatized (II and III) layers. Fe-vernadite and Mn-feroxygite are the major ore minerals in all studied crusts and their layers. Small contents of vernadite, asbolane–buserite, and goethite are registered. Crusts of guyots on the rise are characterized by a stable concentration of heavy and rare metals (Cotot, Ni, Cu, Zn, Pb, Mo, and Cd) independently of their latitudinal location. © 2015, Pleiades Publishing, Ltd.

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